Self-deception can do serious harm when it limits people from seeing important warning signs, or it leads people to overlook serious problems, or it causes people to see the world through rose coloured glasses or drives people to do others harm. Such neglect can promote emotional, mental or physical damage (e.g., infidelity, violence and abuse, substance abuse, selfishness and so on).
Submitting to the world
We can fool ourselves into believing that we can serve God and get away with submitting to the dictates of men. God also says that He is a jealous God (Exodus 34:14, Exodus 20:5). Pretending that God is not what He is would be a very serious example of self-delusion that could lead to harm for ourselves and our offspring for generations.
Exodus 20:5 [KJV] Thou shalt not bow down thyself to them, nor serve them: for I the LORD thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me;
Matthew 6:24 [KJV] No man can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon.
Deuteronomy 11:16-17 [KJV] Take heed to yourselves, that your heart be not deceived, and ye turn aside, and serve other gods, and worship them; [17] And then the LORD’S wrath be kindled against you, and he shut up the heaven, that there be no rain, and that the land yield not her fruit; and lest ye perish quickly from off the good land which the LORD giveth you.
An exercise in Futility
Eliphaz identifies this problem in one of his addresses to Job. He begins by castigating people who defend their actions according to their own reasoning instead of looking to God. Remember that Job's antagonists are all pointing out to Job that he is defending his sins.
Job 15:31-35 KJV Let not him that is deceived trust in vanity: for vanity shall be his recompence. 32 It shall be accomplished before his time, and his branch shall not be green. 33 He shall shake off his unripe grape as the vine, and shall cast off his flower as the olive. 34 For the congregation of hypocrites shall be desolate, and fire shall consume the tabernacles of bribery. 35 They conceive mischief, and bring forth vanity, and their belly prepareth deceit.
In the case of Job, Eliphaz was accusing the wrong person. Job knew that he had done none of those things. In his case the source of the problem was elsewhere. Even though Job knew that he was innocent of what he was being accused he never lost faith in God as his hope.
Job 19:25-26 KJV For I know that my redeemer liveth, and that he shall stand at the latter day upon the earth: 26 And though after my skin worms destroy this body, yet in my flesh shall I see God:
And when Job got more understanding he realised that he God was worthy of far more respect and honour than he had been given credit for.
Job 42:5-6 KJV I have heard of thee by the hearing of the ear: but now mine eye seeth thee. 6 Wherefore I abhor myself, and repent in dust and ashes.
We all have foolish things in our past and it is only later that we realise our stupidity so the the practical thing is to assume that we are missing something now as well and not be presumptuous. Evil people persist in their futile ways and become increasingly vile.
Titus 3:3 [KJV] For we ourselves also were sometimes foolish, disobedient, deceived, serving divers lusts and pleasures, living in malice and envy, hateful, and hating one another.
II Timothy 3:13-15 KJV But evil men and seducers shall wax worse and worse, deceiving, and being deceived. 14 But continue thou in the things which thou hast learned and hast been assured of, knowing of whom thou hast learned them; 15 And that from a child thou hast known the holy scriptures, which are able to make thee wise unto salvation through faith which is in Christ Jesus.
There is no point to a life in conflict with God. God's way is for building a new society. Paul (and others) made it clear that breaking Gods commandments cannot be tolerated. Without Gods law we would not know where to draw the line. James adds another perspective:
Hurting the people that we love
We also have the disastrous incident with Korah, Dathan, and Abiram in Numbers 16. They were so convinced that they risked the lives of their families and brought destruction on them. No matter what Moses said it did not get through. Are we so different? Is it possible that some of the harm that comes to our families could be on our heads?
It is also suggested that:
Most conflicts are perpetuated by self-deception. Have you ever been convinced that you needed to make a stand and soon after realised that a little more understanding would have accomplished much more?
Most failures in communication are perpetuated by self-deception. One person feels another is unapproachable because they are wealthy or good looking or of the opposite sex etc.
Most breakdowns in trust and accountability are perpetuated by self-deception. One party is hurt by some incident and is now convinced that the other is unreliable or untrustworthy because they interpret the results as treachery.
Other examples of negative self deception include:
A spouse who thinks that he/she can mould the other into who they think is perfect.
The pathological gambler who goes bankrupt betting on a sure thing.
The battered wife who keeps returning to her abuser.
Convincing ourselves that we are "finished" when the job isn't over.
The substance abuser who is convinced that drugs make him/her better.
It is interesting how self deception may work differently depending on whether or not you are the victor. The 2003 US invasion of Iraq was once publicly touted as based, in part, on the mistaken belief that Saddam Hussein harbored weapons of mass destruction. It was thought that it served as a prominent and controversial case of self-deception that was still being examined. Whether or not that is true the references to the US invasion and self deception have now disappeared from prominence. The disappearance makes it no less or more true but may have consequences for whether or not it is repeated.
In the same invasion, former Iraqi Information Minister Mohammed Saeed al-Sahhaf illustrated another well-known instance of self-deception. On April 7, 2003, al-Sahhaf claimed that there were no American troops in Baghdad, and that the Americans were committing suicide by the hundreds at the city's gates. At that time, American tanks were patrolling the streets only a few hundred meters from the location where the press conference was held. al-Sahhaf, whose colorful appearances earned him the nickname "Baghdad Bob" claimed claimed that the reports were provided by authentic sources—many authentic sources
. Baghdad Bob is still a notable reference as indicated by wikipedia https://en.wikipedia.org/wiki/Muhammad_Saeed_al-Sahhaf
Is it possible that anyone in history could have foreseen situations like this?
We are all capable of believing things which we know to be untrue, and then, when we are finally proved wrong, impudently twisting the facts so as to show that we were right. Intellectually, is possible to carry this process for an indefinite time: the only check on it is that sooner or later a false belief bumps up against solid reality, usually on a battlefield
George Orwell (1903 1950)